Entrainment of the Circadian Clock of the Enteric Bacterium <i>Klebsiella aerogenes</i> by Temperature Cycles

Entrainment of the Circadian Clock of the Enteric Bacterium Klebsiella aerogenes by Temperature Cycles

iScience ◽

10.1016/j.isci.2019.09.007 ◽

2019 ◽

Vol 19 ◽

pp. 1202-1213 ◽

Cited By ~ 2

Author(s):

Jiffin K. Paulose ◽

Charles V. Cassone ◽

Kinga B. Graniczkowska ◽

Vincent M. Cassone

Keyword(s):

Circadian Clock ◽

Klebsiella Aerogenes ◽

Enteric Bacterium ◽

Temperature Cycles

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Influence of light and temperature cycles on the expression of circadian clock genes in the mussel Mytilus edulis

Marine Environmental Research ◽

10.1016/j.marenvres.2020.104960 ◽

2020 ◽

Vol 159 ◽

pp. 104960

Author(s):

Emma C. Chapman ◽

Brodie J. Bonsor ◽

Daniel R. Parsons ◽

Jeanette M. Rotchell

Keyword(s):

Circadian Clock ◽

Mytilus Edulis ◽

Clock Genes ◽

Temperature Cycles ◽

Circadian Clock Genes

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The Summer Is Coming: nocte and timeless Genes Are Influenced by Temperature Cycles and May Affect Aedes aegypti Locomotor Activity

Frontiers in Physiology ◽

10.3389/fphys.2020.614722 ◽

2020 ◽

Vol 11 ◽

Author(s):

Rayane Teles-de-Freitas ◽

Gustavo B. S. Rivas ◽

Alexandre A. Peixoto ◽

Rafaela Vieira Bruno

Keyword(s):

Locomotor Activity ◽

Aedes Aegypti ◽

Circadian Clock ◽

Intervention Strategies ◽

Temperature Variations ◽

Temperature Cycles ◽

Rhythmic Expression ◽

Abrupt Changes ◽

Phase Temperature ◽

Circadian Behavior

Mosquitoes exhibit activity rhythms, crucial for the transmission of pathogens, under the control of a circadian clock. Aedes aegypti is one of the world’s leading vectors. For decades, several studies have linked the rise in ambient temperature with the increase in their activity. Here, we identify candidate genes whose expression is influenced by temperature cycles and may affect Aedes locomotor activity. We observed that timeless completely lost its rhythmic expression in light/dark, with out-of-phase temperature cycles, and by RNAi mediated knockdown of nocte, an important gene for Drosophila circadian synchronization by temperature cycles. Thus, timeless and nocte are important genes for synchronization by temperature cycles in Aedes aegypti. To reinforce our findings, we simulated in the laboratory the gradual temperature fluctuations that were as close as possible to daily temperature variations in Brazil. We observed that the activity and the expression of the molecular circadian clock of Ae. aegypti differs significantly from that of mosquitoes subjected to constant or rectangular abrupt changes in temperature. We suggest that for understanding the circadian behavior of Aedes with possible implications for intervention strategies, the seminatural paradigm needs to replace the traditional laboratory study.

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Tuning the phase of circadian entrainment

Journal of The Royal Society Interface ◽

10.1098/rsif.2015.0282 ◽

2015 ◽

Vol 12 (108) ◽

pp. 20150282 ◽

Cited By ~ 44

Author(s):

Grigory Bordyugov ◽

Ute Abraham ◽

Adrian Granada ◽

Pia Rose ◽

Katharina Imkeller ◽

...

Keyword(s):

Experimental Data ◽

Mathematical Models ◽

Circadian Clock ◽

Published Data ◽

Jet Lag ◽

Transient Phase ◽

Phase Dynamics ◽

Temperature Cycles ◽

External Cues ◽

Asymptotic Phase

The circadian clock coordinates daily physiological, metabolic and behavioural rhythms. These endogenous oscillations are synchronized with external cues (‘zeitgebers’), such as daily light and temperature cycles. When the circadian clock is entrained by a zeitgeber, the phase difference ψ between the phase of a clock-controlled rhythm and the phase of the zeitgeber is of fundamental importance for the fitness of the organism. The phase of entrainment ψ depends on the mismatch between the intrinsic period τ and the zeitgeber period T and on the ratio of the zeitgeber strength to oscillator amplitude. Motivated by the intriguing complexity of empirical data and by our own experiments on temperature entrainment of mouse suprachiasmatic nucleus (SCN) slices, we present a theory on how clock and zeitgeber properties determine the phase of entrainment. The wide applicability of the theory is demonstrated using mathematical models of different complexity as well as by experimental data. Predictions of the theory are confirmed by published data on Neurospora crassa strains for different period mismatches τ − T and varying photoperiods. We apply a novel regression technique to analyse entrainment of SCN slices by temperature cycles. We find that mathematical models can explain not only the stable asymptotic phase of entrainment, but also transient phase dynamics. Our theory provides the potential to explore seasonal variations of circadian rhythms, jet lag and shift work in forthcoming studies.

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Circadian Clocks in the Regulation of Neurotransmitter Systems

Pharmacopsychiatry ◽

10.1055/a-1027-7055 ◽

2019 ◽

Author(s):

Jana-Thabea Kiehn ◽

Frank Faltraco ◽

Denise Palm ◽

Johannes Thome ◽

Henrik Oster

Keyword(s):

Circadian Clock ◽

Cognitive Functions ◽

Current Knowledge ◽

Circadian System ◽

Circadian Clocks ◽

Earth’S Rotation ◽

Earth's Rotation ◽

Neurotransmitter Systems ◽

Temperature Cycles ◽

Health And Disease

AbstractTo anticipate and adapt to daily recurring events defined by the earth’s rotation such as light-dark and temperature cycles, most species have developed internal, so-called circadian clocks. These clocks are involved in the regulation of behaviors such as the sleep-wake cycle and the secretion of hormones and neurotransmitters. Disruptions of the circadian system affect cognitive functions and are associated with various diseases that are characterized by altered neurotransmitter signaling. In this review, we summarize the current knowledge about the interplay of the circadian clock and the regulation of psychiatric health and disease.

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Circadian clock neurons maintain phase control over daily behavioral activity patterns under diverse environmental conditions

10.1101/2020.06.02.128918 ◽

2020 ◽

Author(s):

Clara Lorber ◽

Ralf Stanewsky ◽

Angélique Lamaze

Keyword(s):

Circadian Clock ◽

Environmental Conditions ◽

Activity Patterns ◽

Time Of Day ◽

Constant Light ◽

Behavioral Activity ◽

Activity Increase ◽

Temperature Cycles ◽

Activity Peak ◽

Deterministic Function

AbstractProper timing of rhythmic locomotor behavior is the consequence of integrating environmental conditions and internal time within the circadian clock. The 150 clock neurons in the Drosophila melanogaster brain are organized in various clusters, controlling different aspects of the daily activity rhythms. For example, during regular 12 hr light : 12 hr dark cycles at constant temperature (LD), so called Morning (M) neurons control the activity peak in the morning, while Evening (E-) neurons regulate the activity increase at the end of the day. During the remaining times of day and night, flies are inactive, giving rise to the crepuscular behavior observed in LD. Here, we investigate if the same neuronal groups also control behavioral activity under very different environmental conditions of constant light and temperature cycles (LLTC). While the morning activity is completely absent in LLTC, a single pronounced activity peak occurs at the end of the thermophase. We show that the same E-neurons operating in LD, also regulate the evening peak in LLTC. Interestingly, neuronal activity of E-neurons is inversely correlated with behavioral activity, suggesting an inhibitory action on locomotion. Surprisingly, the E-cells responsible for synchronization to temperature cycles belong to the clock neurons containing the circadian photoreceptor Cryptochrome, previously suggested to be more important for synchronization to LD. Our results therefore support a more deterministic function of the different clock neuronal subgroups, independent of specific environmental conditions.Significance statementMaster circadian clocks in the brains of mammals and fruit fly are composed of neurons expressing varying types of neuropeptides and transmitters. This diversity along with anatomical differences indicate diverse functions of different clock neurons. In Drosophila, so-called Morning (M) and Evening (E) neurons control locomotor activity at the respective time of day during normal day/night (LD) cycles. Recent reports point to a certain degree of plasticity with regard to circadian clock neuron function, depending on specific environmental conditions. Here we show that one neuronal group, the E-neurons, instead behave as if hard-wired to their output targets. Surprisingly they direct activity to occur during the evening both under LD conditions, as well as during temperature cycles in constant light.

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